I've been playing this game on and off since its release. Left in bc for 3 months...came back. Played in wrath hardcore, and quit for cata's release. A lot of it (except goblins and deathwing) just didn't appeal to me. Deathwing turned out to be a disappointment it seems as an end boss anyway.
Came back for mists, and played regularly, and because of drama with the 2 guilds i was in, the one raid guild falls apart and everyone disperses. The other pvp guild i was in, guild leader picked up guild and moved it to another server without telling anyone except a few other people. So i stopped playing last season because I didn't feel like finding another guild and seeing the gear was a re-skin i said meh, I'll wait until near the end.
Around same time(nov-dec), i started playing ffxiv aar. I actually love it. And i started playing it full time and hardcore. Now, i'm at the point where i have no desire to continue playing it and I want to go back to wow again -_-. I've tried quite a few mmo's and this is what happens every-time. Not sure exactly what is, but....
I think for me it's the history i have with it, the vast universe and lore, and the time I have invested into the game. Not to mention...the game is continually polished and had come a long way from where it was....good or bad. How about everyone else? Or what was the last straw that stopped you from coming back period? A better mmo? Or something about WoW itself?